The invention relates generally to the field of ultrasonic imaging. More particularly, the invention relates to multiple beam beamforming for ultrasonic imaging.
Multiple beam beamforming techniques, sometimes called parallel beamforming, form two or more receive beams in response to a single transmit beam. For example, one broad beam is transmitted and two or more receive beams are simultaneously formed from responsive echo signals.
Due to the parallel processing of data, image artifacts may be generated. The image artifacts are manifested in geometrical distortion, brightness variation, blockiness and/or degraded lateral resolution. One proposed solution to reduce the presence of these artifacts is provided in U.S. Pat. No. 5,667,373 to Wright et al. Coherent data along a same line is averaged, and data from two different lines are phase adjusted and interpolated coherently to form a synthized line of data. One problem with the Wright solution is the performance of process intensive interpolation to create the synthesized beam.
The present invention is defined by the following claims, and nothing in this section should be taken as a limitation on those claims. By way of introduction, the preferred embodiments described below include methods and systems for forming received ultrasound data. Multiple receive beams are formed in response to each transmit beam. Two or more receive beams responsive to different transmit beams are formed along a same line. The co-linear receive lines are combined to remove artifacts. The combination is responsive to the geometric distortion. For example, the receive lines are weighted as a function of the distance from any receive line to the associated transmit line. In one embodiment, four receive lines are obtained for each transmit line. Two of the four receive lines for one transmission are co-linear with a respective two of the four receive lines of another transmission. Data for each of the co-linear lines is combined. Unequal weights are used for combining each set of co-linear data due to the different distances between each receive line and the associated transmit lines.
A first aspect is a method for forming received ultrasound beams for an ultrasound image. The method comprises transmitting at least two adjacent transmit beams; responsive to the transmitting, forming at least two adjacent receive beams for each of the transmit beams; and combining at least two of the received beams. The combined received beams are disposed at approximately the same location, and at least two of the combined received beams are formed from different transmit beams.
A second aspect is a system for producing output frames in an ultrasound imaging system. The system comprises transducers, a beamformer, digital echo processors, and a scan converter. The transducers are adapted to transmit and receive ultrasound pulses. The beamformer is adapted to simultaneously generate at least four receive beams in response to a transmit beam. Each digital echo processor is adapted to combine data corresponding to at least two receive beams emanating from the same target location. The scan converter includes processing resources adapted to process the combined receive beam data to form an output frame.
In a third aspect, a method for forming received ultrasound data is provided. At least first and second beams are transmitted along first and second different scan lines. At least first and second receive beams are formed in response to the first transmitted beam. At least third and fourth receive beams are formed in response to the second transmit beam. The third receive beam is co-linear with the second receive beam. The second receive beam is combined with the third receive beam in response to unequal weights. A system including a transducer, beamformer and processor for implementing the above method may also be provided.
In a fourth aspect, another method for forming received ultrasound data is provided. Acoustic energy is transmitted along first and second lines. The first line is spatially different than the second line. A first set of data representing at least four receive lines is formed in response to the transmission along the first line, and a second set of data representing at least four receive lines is formed in response to the transmission along the second line. At least first and second receive lines of the first set are co-linear with third and fourth receive lines, respectively, of the second set. Data of the first receive line is combined with data of the third receive line, and data of the second receive line is combined with data of the fourth receive line. A system including a transducer, beamformer and processor for implementing the above method may also be provided.
In a fifth aspect, yet another method for forming received ultrasound data is provided. Acoustic energy is transmitted along first and second transmit lines. The first transmit line is spatially different than the second transmit line. A first set of data representing at least two receive lines is formed in response to the transmission along the first transmit line. A second set of data representing at least two receive lines is formed in response to the transmission along the second transmit line. At least a first receive line of the first set is co-linear with a second receive line of the second set. Data of the first receive line is combined with data of the second receive line in response to first and second weights. The first weight is a function of a distance of the first receive line from the first transmit line, and the second weight is a function of a distance of the second receive line from the second transmit line. A system including a transducer, beamformer and processor for implementing the above method may also be provided.
Further aspects and advantages of the invention are discussed below in conjunction with the preferred embodiments.